monitor network requests to see if a webpage has google analytics enabled

Question

Which requests should I monitor to see if a webpage has Google Analytics enabled and active?

Is is analytics.js?

Or maybe a GIF request to www.google-analytics.com, is that revealing?

Answer 1

For Universal Analytics, look for GIF image requests sent to the endpoint google-analytics.com/collect (cf. https://developers.google.com/analytics/devguides/collection/analyticsjs/sending-hits#hits_hit_types_and_the_measurement_protocol).